Vintage Harmony 400A Tube Guitar Amp 50C5 / 12AU6 / 35R4 Lo-Fi Blues Tone
Sunday, February 22nd, 2026





Vintage Harmony 400A Guitar Amplifier. This is a fully working Harmony 400A, a super cool low-watt tube guitar amp from the 1950s-60s. It runs a single-ended tube circuit with the following tubes. Estimated at 3-5 watts, this amp is not very loud, making it perfect for practice, harmonica, or mic’d recording. It delivers classic, warm lo-fi breakup, especially with single-coil pickups. Original small speaker approx. 6 Original Jensen speaker. Volume & Tone controls. Typical vintage hum/crackle when adjusting knobs. Cosmetic wear consistent with age (see photos). ? Tone: Smooth overdrive at low volume. Perfect for slide guitar, harmonica, and retro blues tone. Think early Chess Records or garage band vibes.




